Camera module electrical architecture

ABSTRACT

A camera module includes a lens carrier that houses a lens, electrical components of optical path modifiers positioned on the lens carrier, an image sensor, and a controller that is to generate commands for operating the optical path modifiers. A printed circuit assembly positioned on the lens carrier is electrically coupled to suspension wires. The printed circuit assembly includes a printed circuit that has installed thereon a serial bus communications interface circuit that is to receive the commands from the controller through one of the suspension wires, and a translation circuit that is to translate the commands into control signals that are to operate or drive the optical path modifiers via the electrical components and according to the commands, respectively. Other embodiments are also described.

This is a continuation application which claims priority to U.S. patentapplication Ser. No. 14/940,013 filed Nov. 12, 2015, which claims thebenefit of the earlier filing date of U.S. Provisional Application No.62/206,766 filed Aug. 18, 2015.

FIELD

An embodiment of the invention is related to camera modules, and morespecifically to techniques for communicating with electrical componentsthat are positioned on a lens carrier of the camera module. Otherembodiments are also described.

BACKGROUND

Camera modules are incorporated into a variety of consumer electronicdevices, including smartphones, mobile audio players, personal digitalassistants, laptop computers, and desktop computers. There is a constantdrive to add additional features to these cameras modules whilemaintaining a compact size. For example, one feature that is desirablein camera modules is an autofocus (AF) feature that automaticallyadjusts focal distance so that an image captured by the camera module isin sharp focus. Another feature that is desirable in camera modules isan optical image stabilization (OIS) feature that compensates forunintended movement of the camera module when capturing an image/video(e.g., due to user hand shake or other vibration).

OIS is performed by detecting movement of the camera module and thencounteracting that movement, for example, by moving the lens carrier ofthe camera module in an opposite direction of that movement. This can beachieved by suspending the lens carrier using flexible suspension wiresthat sway so as to allow the lens carrier to move in directionsorthogonal to an optical axis of a lens of the camera module. The lenscarrier can be moved using a force generated by a magnet and a coilcarrying electric current (e.g., a Lorentz force). The flexiblesuspension wires can also be used to carry the electrical coil currentin order to perform AF.

SUMMARY

Adding features such as aperture control and optical zoom, in additionto AF and OIS, to a camera module may require adding more wires to anOIS suspension mechanism or substantially redesigning and reconstructingthe OIS suspension mechanism so that additional electricalcurrent/signals can be transmitted to the lens carrier to operate ordrive the additional features. However, there is a limit to the numberof wires that can be added to the OIS suspension mechanism due tomechanical constraints. Also, redesigning and reconstructing the OISsuspension mechanism each time a new feature is to be added to the lenscarrier is not practical, particularly when new features are expected tobe added at a rapid rate.

An embodiment of the invention is a camera module that implements anarchitecture for electrically communicating with multiple electricalcomponents of optical path modifiers, wherein the electrical componentsare positioned in a lens carrier. The camera module includes an imagesensor, and the lens carrier which houses an imaging lens. Multipleoptical path modifiers are positioned on the lens carrier. Multiple OISsuspension wires suspend the lens carrier. A controller generatescommands for operating the optical path modifiers, where the controlleris positioned outside of the lens carrier. The camera module furtherincludes a printed circuit assembly positioned on the lens carrier thatis electrically coupled to the suspension wires. The printed circuitassembly includes a printed circuit that has installed thereon a serialbus communications interface (SBCI) circuit that is to receive thecommands from the controller through one or more of the suspensionwires. Also installed on the printed circuit is a translation circuitthat is to translate the commands into multiple control signals, wherethe latter are to operate or drive the electrical components of theoptical path modifiers (according to the respective commands.) In otherwords, the SBCI circuit signals the electrical components to behave inaccordance with the commands, respectively. The OIS suspension wires arethus dual purposed for suspending the lens carrier for OIS and forserial bus communications, while the lens carrier also serves as aplatform for the SBCI and electrical control signal translationcircuitry, enabling a camera module architecture that can be more easilyscaled with additional features.

In another embodiment, one of the optical path modifiers is an autofocus(AF) mechanism that includes an AF voice coil motor and a number ofconductive springs that set a default Z-position of the lens carrier(while the OIS suspension wires allow the carrier to move in the x-yplane). The printed circuit assembly is coupled to the OIS suspensionwires through one or more of the AF conductive springs, such that thecommands or electrical power (for driving an optical path modifier) isreceived in the printed circuit assembly through the one or more AFsprings.

In yet another embodiment, one or more sensors, and optionally one ormore optical path modifiers, are positioned on a magnet holder of acamera module that also includes a lens carrier. The OIS suspensionwires are fixed to the magnet holder, as are two or more autofocus (AF)springs which set a default position of the lens carrier (for verticaldisplacement of the lens carrier.) A controller receives sensor datafrom the sensors, and may also generate commands for operating theoptical path modifiers. The controller is positioned outside of the lenscarrier and outside of the magnet holder. The camera module includes aprinted circuit assembly positioned on the magnet holder and which iselectrically coupled to the OIS suspension wires. The printed circuitassembly includes a printed circuit that has installed thereon a serialbus communications interface (SBCI) circuit that is to transmit thesensor data to the controller (through one or more of the OIS suspensionwires.) It may also receive commands from the controller, through one ormore of the OIS suspension wires. A translation circuit (not shown) thatmay have similar functionality as the translation circuit 180 describedabove may also be installed on the printed circuit 270; the translationcircuit may translate a command (received from the controller) into acontrol signal using any combination of analog and digital circuitry asneeded, so that the control signal can operate or drive one of theoptical path modifiers (according to the command.) For this purpose, thetranslation circuit may also include power conversion circuitry such asa dc-dc converter to produce the control signal with the voltage levelsneeded by its optical path modifier. Thus, the OIS suspension wires aredual purposed for suspending the magnet holder and lens carrier for OIS,and for serial bus communications, while the magnet holder also servesas a platform for the sensors and for the SBCI (and optionally for anoptical path modifier and its control signal translation circuitry),enabling a camera module architecture that can be more easily scaledwith additional features.

In one embodiment, there may be a pair of displacement sensors installedon the printed circuit (on the magnet holder), to sense horizontaldisplacement of the magnet holder; the SBCI circuit may in that casecollect or receive sensor data from the pair of displacement sensors,and transmit the sensor data to the controller through one or more ofthe OIS suspension wires, to provide optical path position feedback toan OIS control algorithm that may be running in the controller. Inanother embodiment, a component of the optical path modifier (on themagnet holder) may be an autofocus driver circuit installed on theprinted circuit, on the magnet holder. An example is a voice coil motor(VCM) driver circuit that is electrically coupled to an AF coil of a VCMactuator (also referred to as an AF actuator), where the AF coil isinstalled on the lens carrier; two or more of the AF springs areconductive and in this case serve to carry the AF coil current, betweenthe VCM driver circuit on the magnet holder and the AF coil on the lenscarrier. The SBCI in that case also serves to receive an AF command fromthe controller (through the OIS suspension wire) that may indicate adesired position of an autofocus lens. The command may be forwarded tothe VCM driver circuit that is also on the printed circuit, which inturn provides the appropriate electrical drive to the AF coil (e.g., anAF coil current) through one or more of the AF springs, in order to forexample move the lens carrier (which carries an imaging lens) to thedesired focus position.

The above summary does not include an exhaustive list of all aspects ofthe present invention. It is contemplated that the invention includesall systems and methods that can be practiced from all suitablecombinations of the various aspects summarized above, as well as thosedisclosed in the Detailed Description below and particularly pointed outin the claims filed with the application. Such combinations haveparticular advantages not specifically recited in the above summary.

BRIEF DESCRIPTION OF THE DRAWINGS

The embodiments of the invention are illustrated by way of example andnot by way of limitation in the figures of the accompanying drawings inwhich like references indicate similar elements. It should be noted thatreferences to “an” or “one” embodiment of the invention in thisdisclosure are not necessarily to the same embodiment, and they mean atleast one. Also, a given figure may be used to illustrate the featuresof more than one embodiment of the invention in the interest of reducingthe total number of drawings and, as a result, not all elements in thefigure may be required for a given embodiment.

FIG. 1 is a diagram illustrating a side cross-sectional view of a cameramodule, according to some embodiments.

FIG. 2 is a diagram illustrating a top cross-sectional view of a cameramodule, according to some embodiments.

FIG. 3 is a block diagram illustrating some constituent components of acamera module and communication paths between the components, accordingto some embodiments.

FIG. 4 is a diagram illustrating a side cross sectional view of a cameramodule according to another embodiment.

FIG. 5 is a diagram of a top cross sectional view of the embodiment ofFIG. 4.

FIG. 6 is a diagram illustrating a portable handheld computing device inwhich a camera module may be implemented, according to some embodiments.

DETAILED DESCRIPTION

Several embodiments with reference to the appended drawings are nowexplained. Whenever aspects of the embodiments described here are notexplicitly defined, the scope of the disclosure is not limited only tothe parts shown, which are meant merely for the purpose of illustration.Also, while numerous details are set forth, it is understood that someembodiments may be practiced without these details. In other instances,well-known circuits, structures, and techniques have not been shown indetail so as not to obscure the understanding of this description.

Embodiments provide an architecture to communicate with multiple opticalpath modifiers positioned on a lens carrier of a camera module thatemploys an OIS suspension mechanism. For example, embodiments allow forcommunication with various optical path modifiers such as an autofocus(AF) control mechanism, an adjustable diaphragm or aperture controlmechanism, and an optical zoom control mechanism. Embodiments achievethis by providing a printed circuit assembly positioned on the lenscarrier. The printed circuit assembly has installed thereon an interfacecircuit and a translation circuit. The interface circuit has circuitryto receive control messages or commands for operating one or moreoptical path modifiers. The translation circuit has circuitry totranslate or convert the commands into control signals for operating ordriving the optical path modifiers according to the respective commands.Theoretically, embodiments of the architecture described herein allowfor communication with any number of optical path modifiers positionedon the lens carrier, while keeping the existing OIS suspension mechanism(practically, the number may be limited only by the amount of spaceavailable on the lens carrier and the heat generated by the printedcircuit assembly and the optical path modifiers). As such, additionaloptical path modifiers (and thus additional features) can be added tothe lens carrier without adding more wires to the OIS suspensionmechanism and without substantially redesigning/reconstructing the OISsuspension mechanism. Embodiments are described herein in additionaldetail below.

FIG. 1 is a diagram illustrating a side cross-sectional view of a cameramodule, according to some embodiments. The camera module 100 includes alens carrier 105 and a magnet holder 110 that are suspended over astationary plate 120 by optical image stabilization (OIS) suspensionwires 115. The OIS suspension wires 115 are flexible wires that extendparallel to an optical axis 130 of the lens carrier 105 or camera module100. Each of the OIS suspension wires 115 may be anchored to thestationary plate 120 and to the magnet holder 110, and can sway suchthat it extends obliquely to the optical axis 130 (as shown by thedotted line). This allows the lens carrier 105 (and the magnet holder110) to move in a direction orthogonal to the optical axis 130 toperform OIS (i.e., in the X-direction and Y-direction, or x-y plane).The lens carrier 105 may have a plastic body that defines an opticalpath through which light from a scene to be photographed enters thecamera module 100 to reach an image sensor 155.

The lens carrier 105 including its plastic body may house or supportthereon one or more components of one or more optical path modifiers. Anoptical path modifier may be any mechanism that modifies the opticalpath taken by light that enters the camera module 100 and that is thenincident upon the image sensor 155 (to form an optical image of thescene being captured) under electrical control. An optical path modifierhas an electrical component through which modification of the light pathcan be achieved. Examples of an optical path modifier include i) anautofocus, AF, mechanism having a moveable focusing lens, an AF drivecircuit 135 and AF coil 140 to perform autofocus, ii) a variablediaphragm/aperture control mechanism 145 having an electro chromicdevice or a mechanical iris diaphragm, and iii) an optical zoom controlmechanism (e.g., zoom lens 150 and its associated zoom lens drivercircuit) to perform optical zoom. Note that an optical path modifier mayhave one of its components positioned off the lens carrier 105. Forexample, the AF mechanism described below has an electromagnetic motorwhose magnet is part of the magnets 160, which is located within amagnet holder 110, while the AF coil 140 is attached to or held by thelens carrier 105—see FIG. 1.

The lens carrier 105 may also house or carry static optical elements 153(e.g., one or more imaging lenses, filters, and/or mirrors) to filter,redirect or further focus the light entering the camera module 100 ontothe image sensor 155. As shown, the image sensor 155 may be positionedin a flat (horizontal) arrangement, at or below the stationary plate120. The stationary plate 120 may include a cut-out portion ortransparent portion (not shown) through which light from the scenetravels through the lens carrier 105 and onto the image sensor 155. Theimage sensor 155 converts the light into electrical signals to generatea digital image.

The magnet holder 110 may be made of a plastic body, and includesmagnets 160 held by the body that are part of an electromagnetic motorof an optical path modifier. For example, the motor may be an AF motorthat also includes an AF coil 140 (part of an autofocus voice coilmotor), used for controlling the movement of the lens carrier 105 in adirection substantially parallel to the optical axis 130 (e.g., in theZ-direction) to perform AF. The magnets 160 may also be part of anotherelectromagnetic motor, which includes the OIS coil 125, used forcontrolling movement of the holder 110 and the carrier 105 in directionssubstantially orthogonal to the optical axis 130 (e.g., in theX-direction and Y-direction) to perform OIS, as will be described inadditional detail below. In the example shown in FIG. 1, the OIS coil125 is fixed to the stationary plate 120 (below the magnets 160) and theAF coil 140 is fixed to the lens carrier (e.g., integrated with the lenscarrier 105).

OIS movement of the lens carrier 105 is actuated by driving OIS coil 125(positioned on the stationary plate 120) with electric current togenerate an electric field. A Lorentz force is generated by theinteraction between the electric field generated by the electric currentrunning through the OIS coils 125 and the magnetic field produced by themagnets 160. This Lorentz force may be in a direction orthogonal to theoptical axis 130 and thus moves the lens carrier 105 in the X-directionand Y-direction. As such, the lens carrier 105 and the optical pathmodifiers therein can be moved in the X-direction and Y-direction toperform OIS.

The AF control mechanism is used to perform AF. In one embodiment, theAF control mechanism includes an AF drive circuit 135 positioned on thelens carrier 105 and an AF coil 140 (which may be wrapped around thelens carrier 105). The lens carrier 105 is suspended by AF springs 205such that the lens carrier 105 can move in a direction parallel to theoptical axis 130 (i.e., in the Z-direction). The AF springs 205 aredescribed in more detail below with relation to FIG. 2. The AF drivecircuit 135 can drive the AF coil 140 with electric current to generatean electric field. A Lorentz force is generated by the interactionbetween the electric field generated by the electric current runningthrough the AF coils 140 and the magnetic field produced by the magnets160. This Lorentz force may be in a direction parallel to the opticalaxis 130 and thus moves the lens carrier 105 in the Z-direction. Assuch, the AF control mechanism can move the lens carrier 105 and theoptical path modifiers therein in the Z-direction to adjust the focus oflight on the image sensor 155.

In one embodiment, the variable diaphragm/aperture control mechanism 145includes an electro chromic device. The electro chromic device can beelectrically switched from a transparent state (large aperture) to anon-transparent state (stopped, or small aperture). In one embodiment,the electro chromic device can be electrically controlled to adjust thesize of an opening through which light enters into the camera module100. In another embodiment, a mechanical diaphragm (e.g., an irismechanism) is provided for achieving variable aperture, instead of theelectro chromic device. The diaphragm/aperture control mechanism 145 mayinclude conductive material such as electrically conductive connects 165that provide a contact point for electrical signals to be delivered tothe electro chromic device, or to a motor (not shown) of the mechanicaldiaphragm.

The optical zoom control mechanism is used to perform optical zoom. Inone embodiment, the optical zoom control mechanism includes a zoom lens150 held by the lens carrier 105. In one embodiment, the zoom lens 150is a Piezo lens that can be electrically controlled to move in adirection parallel to the optical axis 130 to thereby increase ordecrease magnification. In another embodiment, the zoom lens 150 is aliquid lens. An electrical drive signal can be applied to the liquidlens to change the optical characteristics of the liquid lens to therebyincrease or decrease magnification. The optical zoom control mechanismmay include conductive material such as electrically conductive connects157 that provide a contact point for electrical signals to be deliveredto control (drive) the optical zoom control mechanism.

There is a growing demand to add more features on the lens carrier 105.However, there is a limit to the number of features that can be added tothe lens carrier 105 because a typical OIS suspension mechanism only hasfour OIS suspension wires 115, and thus only allows fordriving/controlling a limited number of electrically controlled (ordriven) features on the lens carrier 105. For example, prior art cameramodules that support an AF feature typically include an AF drive circuitthat is positioned outside of the lens carrier. The AF drive circuitcontrols movement of the lens carrier by driving electrical current intoan AF coil that is on the lens carrier, through a pair of OIS suspensionwires. This electrical current driven into the AF coils causes a Lorentzforce to be generated that moves the lens carrier in the Z-direction.Since the OIS suspension wires are being used to carry the coil currentfor operating AF, this means that other features such as an aperturecontrol feature and an optical zoom feature cannot be added to the lenscarrier because there are not enough OIS suspension wires that areavailable to carry the electrical current for operating those features.Simply adding more OIS suspension wires to the OIS suspension mechanismmay not be feasible due to mechanical and/or power constraints.

Thus, instead of using the OIS suspension wires 115 to carry theelectrical drive current that directly drives a coil or other feature onthe lens carrier, embodiments use the OIS suspension wires 115 tocommunicate digital control messages or commands to the lens carrier105. Control messages or commands may be high-level instructions (e.g.,digital words) for operating one or more optical path modifiers. Acontrol message can contain one or more commands for actuating anynumber of optical path modifiers. For example, a control message caninclude a command to move the lens carrier 105 in the Z-direction by acertain specified amount (e.g., a focusing lens position or displacementfor AF), another command to change aperture size by a certain amount(e.g., for variable aperture), and yet another command to zoom out by acertain amount (e.g., for optical zoom).

A printed circuit assembly is positioned on the lens carrier 105 thatprocesses the control messages or commands. For this purpose, theprinted circuit assembly includes a printed circuit 170 (e.g., flatcircuit, a flex circuit) and various electronic circuitry that isinstalled on the printed circuit 170 such as a serial bus communicationsinterface (SBCI) circuit 175 and a translation circuit 180. The SBCIcircuit 175 includes circuitry for receiving and transmitting data overa serial bus (e.g., an Inter-Integrated Circuit Communications (I²C)bus). Thus, the SBCI circuit 175 is capable of receiving a controlmessage over a serial bus connection being a pair of the OIS suspensionwires 115. In one embodiment, the SBCI circuit 175 is capable ofreceiving a control message or command using an I²C communicationsprotocol. In other embodiments, the SBCI circuit 175 may communicateusing a different type of serial data communications protocol.

The translation circuit 180 includes circuitry for translating orconverting commands into control signals that are used to operate ordrive optical path modifiers (according to the respective commands). Acontrol signal may be a digital or analog signal that serves to controlan electrical component of an optical path modifier. In one embodiment,a control signal may be an analog or continuous time signal that drives,which may include supplying electrical power to, an electrical componentof a particular optical path modifier; an example is a coil current of amotor, or an input current of a Piezo element. A control signal mayalternatively be a digital signal that indicates a drive level(communicates) to an electrical component of a particular optical pathmodifier; an example is a binary value that specifies a desired level ofcurrent to a voice coil motor driver circuit (which then produces thedesired level of current through a motor's coil, for example), or alevel of voltage to be produced by a driver circuit of anelectro-chromic device. A control signal may alternatively be abi-stable or multi-stable digital or analog signal that indicates anyone of two or more operating states or conditions, for the electricalcomponent of the optical path modifier to take; an example is a signalthat indicates to a driver circuit the aperture stop of a mechanicaliris diaphragm. The translation circuit 180 may include logic circuitry,digital to analog conversion circuitry, analog conditioning circuitry,and power conversion circuitry (e.g., a dc to dc converter) as needed toproduce such control signals to have a format suitable for interfacingwith the electrical components of their respective optical pathmodifiers. For example, the translation circuit 180 may translate orconvert a received autofocus (AF) command to move the lens carrier 105in the Z-direction by a certain amount, into a digital communicationsignal that is received by a digital control interface an AF drivecircuit 135. The latter then responds and produces the correct drivecurrent through the AF coil 140 to move the lens carrier 105 in theZ-direction by that certain amount. The translation circuit 180 may alsotranslate or convert a command to change aperture size by a certainamount, into a drive signal that directly operates or drives an electrochromic device that is part of the variable aperture control mechanism145, to change the size of the opening through which light enters intothe camera module 100 by that certain amount. The translation circuit180 may also translate or convert a command to zoom out by a certainamount, into a digital communication signal that is received by a lensdriver circuit of the optical zoom control mechanism (e.g., for moving azoom lens 150) to zoom out or decrease magnification by that certainamount. In one embodiment, the translation circuit 180 and the SBCIcircuit 175 together act as a demultiplexer (DEMUX) circuit, to spreadthe various control signals out from a single input feed.

In one embodiment, the lens carrier 105 includes laser directstructuring (LDS) conductive traces that electrically couple one or moreconductive traces of the printed circuit assembly to one or more opticalpath modifiers positioned on the lens carrier 105. The LDS traces can beused to route a control signal to an electrical component of anappropriate optical path modifier. For example, the lens carrier 105 mayinclude LDS traces that electrically couple the printed circuit assemblyto the conductive connects 155 of the optical zoom control mechanism andthe conductive connects 165 of the variable aperture control mechanism,respectively. In this way, the lens carrier 105 is able to receivecontrol messages or commands for operating one or more optical pathmodifiers through a single OIS suspension wire 115, and the printedcircuit assembly provides circuitry to translate or convert thehigh-level commands into lower-level control signals each of which isrouted individually to the appropriate optical path modifier, to operateor drive the optical path modifier according to the respective command.

In one embodiment, a controller (not shown) that is positioned outsideof the lens carrier 105 (e.g., near the image sensor 155) generates thecontrol messages or commands and transmits them to the printed circuitassembly (and more specifically, to the SBCI circuit 175) on the lenscarrier 105, through one or more OIS suspension wires 115. The controlmessages may be transmitted to the printed circuit assembly (through oneor more of the OIS suspension wires 115) as digital signals. Thecontroller and the printed circuit assembly can communicate using anysuitable bus communications protocol. In one embodiment, the controllerand the printed circuit assembly communicate using an I²C communicationsprotocol. In one embodiment, the controller and the printed circuitassembly can communicate using an I²C communications protocol and usingall four OIS suspension wires 115A, 115B, 115C, 115D. The first OISsuspension wire 115D is used for supplying electrical power to the lenscarrier 105. The second OIS suspension wire 115C is used for returningelectrical power (e.g., to ground or to a negative voltage supply, V⁻).The electrical power can be used to power the printed circuit assemblyand the optical path modifiers. In one embodiment, the printed circuitassembly routes electrical power received through one OIS suspensionwire 115 to all of the optical path modifiers. The third OIS suspensionwire 115B and fourth OIS suspension wire 115A are used for carrying busdata transmit and bus data receive signals. For example, the third andfourth OIS suspension wires 115B, 115A can be used to carry data to andfrom the printed circuit assembly, e.g., control messages, includingacknowledgment messages indicating successful receipt of data (accordingto for example, an I²C communications protocol).

In one embodiment, a capacitive sensor (not shown) is installed on thelens carrier 105 that can detect and/or measure the state of one or moreoptical path modifiers positioned on the lens carrier 105. For example,the capacitive sensor may be able to detect the current position of thelens carrier 105 in the Z-direction. The SBCI circuit 175 or othercircuitry of the printed circuit assembly may transmit such sensor data(captured by the capacitive sensor) as part of a control message, sentto the controller through one or more OIS suspension wires 115 (e.g.,using an I²C communications protocol or other suitable communicationsprotocol). The controller can use this information as feedback, todetermine parameters for operating the optical path modifiers. Forexample, the controller may receive the current position of the lenscarrier 105 in the Z-direction and use this information to determine inwhich direction and how much the lens carrier 105 needs to move toachieve a desired focus.

In this way, embodiments provide an architecture where an OIS suspensionmechanism with four OIS suspension wires 115 can be used to communicatewith any number of optical path modifiers positioned on the lens carrier105. This allows any number of optical path modifiers to be added to thelens carrier 105 (e.g., to add additional features to the lens carrier105). Practically, the number of optical path modifiers that can beadded to the lens carrier 105 is limited only by the amount of spaceavailable on the lens carrier 105 and the heat that is generated by theprinted circuit assembly and the optical path modifiers, as the heat mayaffect the optical characteristics of the optical elements housed by thelens carrier 105 (e.g., the lenses).

FIG. 2 is a diagram illustrating a top cross-sectional view of thecamera module 10, according to some embodiments. It is to be noted that,for purpose of illustration, the top cross-sectional view hides somecomponents of the camera module 100 and highlights other components ofthe camera module 100.

The top cross-sectional view of the camera module 100 shows the lenscarrier 105 suspended by, in this example, four AF springs 205. The AFsprings 205 are flexible springs that allow the lens carrier 105 to movein a direction parallel to the optical axis 130 (i.e., in theZ-direction), relative to the magnet holder 110. The AF springs 205 areconductive springs that also serve to electrically couple the OISsuspension wires 115 to the printed circuit 170 on the lens carrier 105.As shown in FIG. 2, each AF spring 205 may be affixed at one end to arespective OIS wire 115 (on the magnet holder 110), and at another endto a circuit trace of the printed circuit 170 (on the lens carrier 105).The circuit trace may be one that is connected to a control input or avoltage supply input of the SBCI circuit 175 or the translation circuit180. In one embodiment, each OIS suspension wire 115 may have acorresponding AF spring 205 that electrically couples that OISsuspension wire 115 to the lens carrier 105. In another embodiment,however, there may be fewer AF springs 205 than OIS suspension wires115.

In one embodiment, the camera module 100 includes four OIS suspensionwires 115 and these four OIS suspension wires 115 are used to implementan I²C communications protocol (e.g., for purposes of bi-directionaldigital communication between a controller and components on the lenscarrier 105). In one embodiment, the first OIS suspension wire 115D isfor supplying electrical power (V⁺), the second OIS suspension wire 115Cis for returning electrical power (V⁻), the third OIS suspension wire115B is for carrying transmitter signals (Tx), and the fourth OISsuspension wire 115A is for carrying receiver signals (Rx). Othersignaling and power delivery arrangements through the OIS suspensionwires 115 are possible, e.g. using wires 115B, 115A for uni-directionalsignaling of control messages or commands from the controller to theSBCI circuit 175.

In one embodiment, and as shown in FIG. 2, the printed circuit 170 has acircular opening that allows the printed circuit 170 to be fitted aroundthe variable aperture control mechanism 145 or other optical elementsthat are stacked on the lens carrier 105 in the Z-direction. The printedcircuit 170 may have installed thereon an SBCI circuit 175 and atranslation circuit 180, as described above. The SBCI circuit 175includes circuitry to receive commands or control messages from thecontroller (not shown in FIG. 2) through one or more OIS suspensionwires 115. The translation circuit 180 includes circuitry to translateor convert the commands into control signals for operating or drivingthe electrical components of two or more optical path modifiers,according to the respective commands.

FIG. 3 is a block diagram illustrating some constituent components of acamera module and communication paths between the components, accordingto some embodiments. The camera module 100 includes a controller 305, aprinted circuit assembly 360, and three optical path modifiers (an AFcontrol mechanism 310, a variable aperture control mechanism 320, and anoptical zoom control mechanism 330). The printed circuit assembly 360includes a SBCI circuit 175 and a translation circuit 180 that areinstalled on the printed circuit 170.

The controller 305 may initiate the operation or actuation of one ormore optical path modifiers by transmitting a control message 340A tothe printed circuit assembly 360 on the lens carrier 105. The controlmessage 340A may include one or more commands for operating the opticalpath modifiers. For example, the control message 340A may include acommand 350A for operating the AF control mechanism 310, a command 350Bfor operating the variable aperture control mechanism 320, and a command350C for operating the optical zoom control mechanism 330. Althoughcontrol message 340A contains three commands, other control messages maycontain any number of commands. For example, control message 340Bcontains only one command. In one embodiment, the controller 305 ispositioned outside of the lens carrier 105 and transmits the controlmessages 340 to the printed circuit assembly using an I²C communicationsprotocol. A control message 340 is transmitted to the printed circuitassembly 360 through one of the OIS suspension wires 115, and through aconnected one of the AF springs 205 (see the embodiment of FIG. 2). TheSBCI circuit 175 receives the control message, and the translationcircuit 180 translates or converts the commands contained in the controlmessage into control signals, for operating the optical path modifiersaccording to the respective commands. The printed circuit assembly (andthe LDS conductive traces—not shown) distributes or routes the controlsignals to the appropriate electrical components of the optical pathmodifiers, to operate the optical path modifiers according to thecommands.

For example, the controller 305 may transmit control message 340A to theSBCI 175 in the printed circuit assembly 360. The control message 340Aincludes a command 350A to move the lens carrier 105 in the Z-directionby a certain amount (e.g., for AF), a command 350B to change aperturesize by a certain amount (e.g., for variable aperture), and a command350C to zoom out by a certain amount (e.g., for optical zoom). The SBCIcircuit 175 receives the control message 340A and the commands 350therein (e.g., using an I²C communications protocol). The translationcircuit 180 translates or converts the command 350A (the command to movethe lens in the Z-direction by a certain amount) into a control signalthat will operate or drive the AF control mechanism 310 to move the lenscarrier 105 in the Z-direction by that certain amount. The translationcircuit 180 also translates or converts the command 350B (the command tochange aperture size by a certain amount) into a control signal thatwill operate or drive the variable aperture control mechanism 320 tochange aperture size by that certain amount. The translation circuit 180likewise translates or converts the command 350C (the command to zoomout by a certain amount) into a control signal that will operate ordrive the optical zoom control mechanism 330 to zoom out by that certainamount. The printed circuit assembly 360 forwards each of these controlsignals to the appropriate optical path modifiers to carry out therespective commands 350 contained in the control message 340A. Thecontroller 305 may send a new control message 340 each time thecontroller 305 determines that an update to an optical path modifier isneeded, and it may only include therein the one or more commands 350that are needed to make the update.

Turning now to FIG. 4 and FIG. 5, these are sectional views of otherembodiments that also enable communication with multiple electricalcomponents of a camera module. In these embodiments, an optical systemhas the lens carrier 105 which houses an imaging lens system, such asstatic optical elements 153 (e.g., one or more imaging lenses, filters,and/or mirrors) to focus light that is entering the camera module fromthe scene (to form an optical image on the image sensor 155.) Theimaging lens system may also include a zoom lens 150 (and optionally avariable diaphragm/aperture control mechanism 145 similar to the onedescribed above for other embodiments). The lens carrier 105 issurrounded by the structure of the magnet holder 110 (again similar towhat was described for other embodiments), and is attached to the magnetholder through a number of autofocus (AF) springs (in this case, foursprings 205 a, 205 b, 205 c, and 205 d) which are fixed to the magnetholder 110, again, in this aspect, similar to the embodiments describedabove. The magnet holder 105 supports therein one or more magnets 160that are part of the electric motors of the AF and OIS actuators. Anumber of OIS suspension wires 115 a, 115 b are fixed to the magnetholder. The suspension wires 115 may serve some of the same purposesdescribed above namely to suspend the magnet holder 110 and the attachedlens carrier 105, relative to the image sensor 155, allowing the magnetholder 110 and the lens carrier 105 to move laterally (that is, in theX-Y plane) for purposes of optical image stabilization (OIS). Similar tothe embodiments above, the suspension wires 115 may be affixed at oneend to a stationary plate 120, and at another end (or another portion)to the magnet holder 110, thereby allowing the magnet holder and lenscarrier to sway sideways, in accordance with an actuation signal (orelectric current) being driven through the OIS coil 125.

In contrast to the embodiments described above however, in the case ofFIG. 4 and FIG. 5, there is a printed circuit 270 that is positioned onthe magnet holder 110 (e.g. on a top flat surface of a molded plasticbody of the magnet holder, as depicted). The printed circuit 270 hasconductive traces or lines therein (not shown) that serve toelectrically couple or route one or more circuits that are installed onthe printed circuit 270, to the suspension wires 115 a, 115 b (noting ofcourse that there may be more than two suspension wires, such as in theembodiments described above in which there are third and fourthsuspension wires 115 c, 115 d). For instance, the printed circuit 270has installed thereon a serial bus communications interface (SBCI)circuit 175, which serves to transmit sensor data produced by adisplacement sensor 272, over the OIS suspension wires. A translationcircuit (not shown) may also be included on the printed circuit 270, ifneeded to perform any signal format translation, between the sensors 272and the SBCI circuit 175. Thus, conductive traces are provided in theprinted circuit 270 that electrically couple the sensors 272 to the SBCIcircuit 175, and also electrically couple the SBCI circuit 175 to thesuspension wires 115. In one embodiment, the suspension wire 115 a is apower supply or Vbus line, 115 c is a power return (e.g., ground) line,115 b is a serial bus communications clock line, and 115 d is the serialbus communications data line (e.g., in accordance with an I²C protocolor other suitable serial bus communications technology.)

The displacement sensor 272 serves to sense horizontal displacement (forexample in either the X or Y direction, or both) of the magnet holder110 and the lens carrier 105, while the lens carrier 105 has a defaultposition that is set in the vertical displacement direction, by the AFsprings 205. Using the coordinate system shown in the figures then, thedisplacement by the sensors 272 is sensed in the X-Y plane, whereas theAF springs 205 are attached to the lens carrier 105 and to the magnetholder 110 in order to set a default position of the lens carrier 105for vertical displacement of the lens carrier 105, that is in thedirection of the Z-axis as shown in the figures. The displacement sensor272 may be installed on the printed circuit 270 (e.g., soldered directlyto conductive traces in the printed circuit 270), or it may be installeddirectly on a plastic body of the magnet holder 110 (e.g., electricallycoupled through LDS conductive traces formed on the plastic body of themagnet holder, to the conductive traces in the printed circuit 270.)

Still referring to FIG. 4 and FIG. 5, in this example, the displacementsensor 272 is installed on the printed circuit 270, and has twocomponents (a pair of sensors), namely an X component sensor 272 a and aY component sensor 272 b, which together serve to measure displacementin the X and Y directions respectively (in a horizontal plane ordirection.) Each of these sensors 272 a, 272 b may be a capacitivesensor that senses the distance of an air gap between (or displacementof) its moveable capacitor plate relative to a complementary, fixedcapacitor plate; the latter is formed as a conductive enclosure 274 thatsurrounds the magnet holder 110 and that may be affixed at its bottomend to the stationary plate 120 below it. The conductive enclosure 274(and hence the complementary, fixed capacitor plate of each sensor 272a, 27 b) may be directly connected to a power supply return, e.g.,ground as shown. The conductive enclosure 274 may otherwise also serveto protect the electronics and mechanical features of the lens carrier105 and magnet holder 110 of the camera module 100.

In another embodiment, the printed circuit 270 also has installedtherein the autofocus drive circuit 135, which is deemed an electricalcomponent of an optical path modifier (an autofocus mechanism); thus, incontrast to the embodiment of FIG. 2, the AF drive circuit 135 is now onthe magnet holder 110 rather than on the lens carrier 105. An example ofthe AF drive circuit 135 is a voice coil motor (VCM) driver circuit. TheAF drive circuit 135 is electrically coupled to the AF coil 140 of a VCMactuator (AF actuator), where the AF coil 140 is installed on the lenscarrier 105, through conductive traces formed in the printed circuitthat are coupled to two or more of the AF springs 205, respectively. Thelatter are conductive and, in this case, serve to carry the variable, AFcoil current, from the AF drive circuit 135 on the magnet holder 110(AF+) to the AF coil 140 on the lens carrier 105, and back (AF−). Thus,at least two of the AF springs 205 are being used differently in thisembodiment, in contrast to FIG. 2 where the AF springs 205 are directlyconnected to the OIS suspension wires 115, respectively, and so carrythe power supply and return (e.g., V+, V−) currents as well as thecommunication signals (e.g., Tx, Rx).

Still referring to FIG. 5, the SBCI 175 in this case also serves toreceive an AF command 350 a from the controller 305 (through one or moreof the OIS suspension wires)—see FIG. 1—that may indicate a desiredfocus position of an imaging lens in the lens carrier 105. The command350 a is then used to signal the AF drive circuit 135 that is also onthe printed circuit 270, where the AF drive circuit 135 in responsegenerates the appropriate control or drive signal to the AF coil 140(e.g., a coil current) through the AF springs 205 and into the AF coil140, in order to for example move the lens carrier 105 (which carries animaging lens) in a vertical direction, to the desired focus position.The command 350 a may thus be viewed as being forwarded to or translatedto the AF drive circuit 135.

FIG. 6 is a diagram illustrating a portable handheld computing device inwhich a camera module may be implemented, according to some embodiments.As shown, the camera module 100, as disclosed herein, may be integratedwithin a housing of a portable handheld computing device 400 such as asmartphone with which a user can conduct a call with a far-end user of acommunications device over a wireless communications network. Theportable handheld computing device 400 may include a touch screen 410that displays a virtual shutter button 420 that allows a user toinitiate image/video capture. When a user actuates the virtual shutterbutton 420, the camera module 100 captures an image/video of a scene.The portable handheld computing device 400 may also include a flashelement 430 that provides lighting when the camera module 100 capturesan image/video. In another embodiment, the camera module 100 may beintegrated within the housing of a tablet computer. These are just twoexamples of where the camera module 100 described herein may be used.However, it is contemplated that the camera module 100 may be used withany type of electronic device in which a camera module 100 is desired,for example, a smartphone, a tablet computer, a camcorder, a laptopcomputing device, a desktop computing device, or a monitor. In oneembodiment, the camera module 100 has the capability to perform AF, OIS,aperture control, and optical zoom (optical path modification), usingthe architecture and techniques described herein for communicating withthe optical path modifiers which are positioned on a lens carrier 105 ofthe camera module 100. It is to be noted that the various optical pathmodifiers mentioned herein are provided by way of example and notlimitation. In other embodiments, the camera module 100 may include adifferent number of optical path modifiers and may include optical pathmodifiers that are different than those described herein. Some or all ofthese optical path modifiers can be controlled or operated using thearchitecture and techniques described herein.

While certain embodiments have been described and shown in theaccompanying drawings, it is to be understood that such embodiments aremerely illustrative of and not restrictive on the broad invention, andthat the invention is not limited to the specific constructions andarrangements shown and described, since various other modifications mayoccur to those of ordinary skill in the art.

What is claimed is:
 1. An optical system, comprising: a magnet holdercomprising a magnet, a displacement sensor, an autofocus drive circuitand a serial bus communications interface (SBCI) circuit; a lens carriercomprising an autofocus coil, the lens carrier suspended relative to themagnet holder via a plurality of autofocus springs, wherein theautofocus drive circuit provides a drive signal to the autofocus coilvia the plurality of autofocus springs; and a plurality of suspensionwires that moveably suspend the magnet holder relative to an imagesensor, wherein the SBCI circuit is electrically coupled to theplurality of suspension wires, the autofocus drive circuit, and thedisplacement sensor, to i) transmit a control signal to the autofocusdrive circuit, in response to receiving an autofocus command through oneor more of the plurality of suspension wires, and ii) transmit throughone or more of the plurality of suspension wires sensor data from thedisplacement sensor.
 2. The optical system of claim 1, wherein the SBCIcircuit and the autofocus drive circuit on the magnet holder receiveelectrical power through a first two of the plurality of suspensionwires.
 3. The optical system of claim 2 wherein the SBCI circuittransmits the sensor data from the displacement sensor through anothertwo of the plurality of the suspension wires.
 4. The optical system ofclaim 1, wherein the lens carrier moves in a direction parallel to anoptical axis of the lens carrier in response to the control signaltransmitted to the autofocus drive circuit.
 5. The optical system ofclaim 1, wherein the magnet holder comprises a printed circuit that iselectrically coupled to the plurality of suspension wires and to theplurality of autofocus springs, and wherein the autofocus drive circuitand the SBCI circuit are on the printed circuit.
 6. The optical systemof claim 1, further comprising: a stationary plate; and an optical imagestabilisation (OIS) coil fixed to the stationary plate that when drivenwith electric current causes the lens carrier to move in a directionorthogonal to an optical axis of the lens carrier, as constrained by theplurality of suspension wires.
 7. The optical system of claim 1,wherein: a first two of the plurality of suspension wires comprise afirst suspension wire for supplying electrical power, and a secondsuspension wire for returning electrical power, and a second two of theplurality of suspension wires comprise a third suspension wire and afourth suspension wire for carrying bus data transmit and bus datareceive signals, or a bus clock signal and a bus data signal.
 8. Theoptical system of claim 1 wherein the sensor data from the displacementrepresents displacement of the magnet holder in a horizontal direction,and the autofocus springs set a default position of the lens carrier ina vertical direction.
 9. The optical system of claim 1 wherein thedisplacement sensor is electrically coupled to the SBCI circuit thoughlaser direct structuring (LDS) conductive traces formed in a plasticbody of the magnet holder.
 10. A camera module comprising: an imagesensor; a magnet holder comprising a magnet, a displacement sensor, anautofocus drive circuit and a serial bus communications interface (SBCI)circuit; a lens carrier comprising an autofocus coil, the lens carriermoveably suspended from the magnet holder by a plurality of autofocussprings, wherein the autofocus drive circuit provides a drive signal tothe autofocus coil via the plurality of autofocus springs; and aplurality of suspension wires anchored to a stationary plate and thatmoveably suspend the magnet holder above the image sensor, wherein theSBCI circuit is electrically coupled to the plurality of suspensionwires, the autofocus drive circuit, and the displacement sensor, and isconfigured to i) signal the autofocus drive circuit in response toreceiving an autofocus command through one or more of the plurality ofsuspension wires, and ii) transmit through one or more of the pluralityof suspension wires sensor data from the displacement sensor.
 11. Thecamera module of claim 10, wherein the SBCI circuit and the autofocusdrive circuit on the magnet holder receive electrical power through afirst two of the plurality of suspension wires.
 12. The camera module ofclaim 11 wherein the SBCI circuit transmits the sensor data from thedisplacement sensor through another two of the plurality of thesuspension wires.
 13. The camera module of claim 11, wherein the lenscarrier moves in a direction parallel to an optical axis of the lenscarrier in response to the autofocus drive circuit being signaled inresponse to the autofocus command.
 14. A portable handheld computingdevice, comprising: a housing; a controller circuit integrated in thehousing; a camera module integrated in the housing, wherein the cameramodule comprises an image sensor, a magnet holder comprising a magnet, adisplacement sensor, an autofocus drive circuit and a serial buscommunications interface (SBCI) circuit, a lens carrier comprising anautofocus coil, the lens carrier moveably suspended from the magnetholder by a plurality of autofocus springs, wherein the autofocus drivecircuit provides a drive signal to the autofocus coil via the pluralityof autofocus springs, and a plurality of suspension wires anchored to astationary plate and that moveably suspend the magnet holder above theimage sensor, wherein the SBCI circuit is electrically coupled to theplurality of suspension wires, the autofocus drive circuit, and to thedisplacement sensor, and is to i) signal the autofocus drive circuit inresponse to receiving an autofocus command through one or more of theplurality of suspension wires, and transmit through one or more of theplurality of suspension wires sensor data from the displacement sensorto the controller circuit.
 15. The portable handheld computing device ofclaim 14, wherein the magnet holder comprises a printed circuit that iselectrically coupled to the plurality of suspension wires and to theplurality of autofocus springs, and wherein the autofocus drive circuitand the SBCI circuit are on the printed circuit.
 16. The portablehandheld computing device of claim 14 wherein the camera module furthercomprises: a stationary plate; and an optical image stabilisation (OIS)coil fixed to the stationary plate that when driven with electriccurrent causes the lens carrier to move in a direction orthogonal to anoptical axis of the lens carrier, as constrained by the plurality ofsuspension wires.
 17. The portable handheld computing device claim 14wherein a first two of the plurality of suspension wires comprise afirst suspension wire for supplying electrical power and a secondsuspension wire for returning electrical power, and a second two of theplurality of suspension wires comprise a third suspension wire and afourth suspension wire for carrying i) bus data transmit and bus datareceive signals or a bus clock signal and a bus data signal.
 18. Theportable handheld computing device of claim 14 wherein the sensor datafrom the displacement represents displacement of the magnet holder in ahorizontal direction, and the autofocus springs set a default positionof the lens carrier in a vertical direction.
 19. The portable handheldcomputing device of claim 14 wherein the displacement sensor iselectrically coupled to the SBCI circuit though laser direct structuring(LDS) conductive traces formed in a plastic body of the magnet holder.